<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./jq-3.6.0.js"></script>
</head>

<body>
    <button>按钮1</button>
    <button>按钮2</button>
    <button>按钮3</button>
</body>
<script>
    $("button").each(function(index, o) {
        console.log(index, o);
    })
    var user = {
        name: 'zhang',
        age: 18
    }
    $.each($("button"), function(i, e) {
        // console.log(i, e);
        // e.onclick = function() {
        //     alert(i)
        // }
    })
    $.each(user, function(i, e) {
        console.log(i, e);
    })
</script>

</html>